var flight={
    "airline":"oceanic",
    number:815
}
var a=flight["number"];
console.log(a);
var b=flight.number;
console.log(b);
var m=flight["m"] ||"{none}";
console.log(m);
var c=flight.e;
console.log(c);//undefined
//var d=flight.e.model;throw "TypeError"
//console.log(d);
var e=flight.e&&flight.e.model;
console.log(e);//undefined
flight["mi"]="lwb";
flight.number=90;
console.log(flight.number)
let name;
for(name in flight){
    //if(typeof flight[name]!='function')
    document.writeln(name+':'+flight[name])
}
console.log(flight.hasOwnProperty('number'));
console.log( flight.hasOwnProperty('constructor') );